The approaches described in this section could be pursued, and are not necessarily approaches that have previously been conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art, merely by virtue of their inclusion in this section.
Generally, power supplies utilizing an isolation transformer include such known topologies as push-pull, half-bridge and full-bridge (described, for example, in Pressman, A. I., “Switching Power Supply Design.” McGraw-Hill, ISBN 0-07-052236-7; and Hnatek, E. R. “Design of solid-state power supplies.” Van Nostrand Reinhold Company, ISBN 0-442-23429-5).
These power supplies have a number of shortcomings, including suffering from flux imbalance, which brings to saturation the core of the transformer, leading to the power supply failure
One of the known approaches to addressing the problem is by utilizing a gapping of the transformer core. Such gapping reduces mutual inductance of the transformer, requiring an increase in the number of winding turns, thus leading to an increase in the core size and resulting in reduced efficiency.
Further, in the foregoing know topologies an additional threat of core saturation is created when the temperature of the core is increasing while saturation flux density decreases, which may lead to the power supply failure. Even further, in these topologies core saturation may occur in a critical situation when input voltage exceeds nominal.